Lithium

I like this discussion. Yeah, those are fair points and some of them circle back to an earlier comment I made on Alpha-N type strategies - they're much nicer if you can actually control the throttles yourself, same goes for TMF type ones where you don't have to worry about anything beyond the throttle itself affecting airflow into the engine. Ultimately seems like we're on a similar page in terms of things we've seen but potentially feel differently about what is acceptable. I have been happy with my experiences with speed density mapping, am aware of it's shortcomings and strengths and it tends to suit the purposes of what I've dealt with but yes. I can't ever see a situation where it's not going to need a lot more calibration effort than MAF does, but then MAF is never going to be as accurate in transient conditions. So far the "best driving" cars I've driven are speed density based but I guess there is the other factor we touched on earlier, some OEMs actually do both to try and get the best of both worlds haha. This definitely gets me wanting to play with M1 Dev again and try dumb ideas.

I clearly easily get carried away, so I'm gonna restrain myself haha. Basically you have MAP/EMAP as a axis - so the pressure ratio across the engine. It flattens the hell out of the map as the effect on fluid flow from pressure ratio is part of what influences the VE map in the first place and also it effectively bakes in more tolerance for the effects of ambient pressure changes and also general outside influences on the tune (such as transient conditions caused by what the external wastegate is doing etc, can be very interesting looking at that ratio when the gate cracks). That is definitely a popular choice for serious hillclimb cars (like Pikes peak levels of altitude change) fwiw, where it isn't just ambient pressure on the intake side that changes for a given throttle angle but with turbo cars the EMAP will go higher and higher for a given manifold pressure target which can cause serious tune drift for something just focussing on intake air density for the fuel model.

Yeah don't get me wrong, AlphaN I generally view of as kindof a "necessary evil" in almost all the cases where I have used it. As you say, where there is unmetered load changes things can get a bit tricky. For me personally, "throttle based load" systems are best done when you can control the throttle with the ECU. The most recent Alpha-N setup I tuned was a Toyota MR-S race car running a Honda K20A with E-throttle on a MaxxECU, and that works great. The big thing is idle control is done via the ECU controlling the throttle, so you (so long as the tune is accurate) have very fine load updates when idle load changes. As a lot of the things you have mentioned come down to, it will only work as well as the tuner and setup allow - a lot of these things introduce compromises, extra effort etc and really like everything when modifying cars you have to consider what is going to best suit the application. Another good point you raise and one thing I've not really mentioned publicly about a lot of my tuning is that (depending on the application) I've often used estimated mass flow type values for axis on load and AFR tables then if there is anything dealing with temperature swings then that will be done with extra adjustment. It makes AFR target tables (and traces through a pull depending on how you've done it) as well as ignition timing tables look quite different but potentially quite a bit more intuitive - like all things though, this kind of thing relies highly on the work you've put into it being accurate and complete. One of my my mates finished a KP Starlet build a couple of years ago and has mega fussy standards overall and he wanted something that was going to be a mix of oldschool raw but also "sorted" so cold starts, driveability etc etc were like clockwork. Like it had to be raw, but refined, and runs a Link ECU. We had many yarns about how to do go about it hardware wise and while the ECU isn't necessarily the best suited to it, I decided to try wrestling into doing things I'd do with a MoTEC or whatever and basically tuned it with two MAP compensated AlphaN VE maps which blended between based off the airflow error between the minimum and maximum request idle air valve work and did the ignition table based off the calculated cyl filling. I'm not saying this is a great idea or anything, buuuuut the car does exactly what he wanted. It's economical, starts and drives better than a lot of factory cars despite having ~280deg cams and ITBs on a nearly 40 year old base engine so I'd argue that one way or another it's a combination which "can do the job". It has no wideband (lots of wires and obvious sensors partly not in fitting of the feel of the car - cool wee car actually: Toyota Starlet | Kelford Cams) yet he has done road trips all around NZ in it covering a variety of altitudes etc with zero issues in terms of shitty running or anything so it can be done even with a crappy old Link ECU. Throttle response is pretty electric, nothing stupid happens, you would not want a thing like this to be with an AFM only load input for all kinds of reasons. Like everything, it partly relies on how much work you want to do to get it "right" and how well you understand an define things. Your comment on how non-linear the relationship between MAP and actual cylinder fill is when you're "in vacuum" is a whole other wild can of worms haha. I fully agree, I feel like you can often tell if someone who has tuned a purely manifold pressure based speed density tune understands (or at least is as OCD as I am) about a lot of the fundamentals of this kind of thing when you look at a VE map. This whole yarn really makes me think of a rant Paul Yaw (Mr Injector Dynamics) had years ago and is very relevant to especially this part of the conversation - if you haven't read it then this may be of interest: That Big Orange Heavy Thing | Injector Dynamics. The relevant bit is "Math doesn't suck" and check it out if you're in an environment where you won't get awkward questions about looking at a webpage with pics of sexy school teachers on it. One way or another it's worth a look. Nice I did ask before but still curious what the specific ITB turbo idiosyncrasies you're talking about? Another thing on the topic of speed density, ever tried IMAP/EMAP based load?

Is that after the initial TMF implementation? I had wondered how well that worked for the same reason @joshuaho96 mentioned - the impression I had from others is it basically used measured pressure drop across the throttle, but I wasn't certain that you'd get a reliable reading post-throttle in all situations. I don't really know what it was (or is) now so treat the whole thing like I need to really know more about it - definitely consider anything I say on this bit as conjecture I have been told the current Emtron setup works well.

Talking about TMF?: I am talking about something along those lines, yes - though I assume you are talking about Emtron's TMF specifically? That is one implementation of a speed density system that happens to use throttle as an input but I wasn't talking about their implementation. In terms of the the pressure ratio across the throttle body concern, yeah I'd "day dreamed" about alternative ideas for determining airflow and had pondered on pressure across a throttle and ruled it out in my head because of that exact reason. I've never used Emtron, let alone their TMF so I don't have a great understanding of how it works or how well it works so I can't really comment on it in context of that. How many cars use "TMF" style speed density and how well it works: I don't think the E9x series BMWs use it though I'm not 100% sure. And to be clear, I am far from claiming I am any authority on these things - much of it is what I remember from conversations over the years with people much smarter than myself so I'm kinda forwarding on my patchy recollection of how I interpreted what I was told about things. In terms of how well it works, I feel like I already said that from what I understand the new Porsche's use this kind of system. Do you doubt the 991 Series Porsches work well? I've only been in a single 991.2 Turbo S and it went like a bat out of hell, but it very much felt sorted beyond "only WOT" type driving by my personal gauge. Super super competent car all round. Like almost too well behaved. Not a fan of Alpha-N/MAP strategies: Can you elaborate? They can be a headfcuk to deal with but I'm not sure they are broken as such. I definitely prefer the concept of pre-throttle pressure vs throttle angle versus an engine flow characterisation map and feel like that's probably the best answer though am not aware of an aftermarket ECU offering that. Yet. Now for the "my view of the world" ramble, again I am no expert so more than happy to be picked apart on this if there is stuff you (or anyone) knows beyond me so this is just my take and limited experience on this general topic. Please excuse any terrible wording or thinking with this, its been a long day at work and if I were wiser I'd write this when my brain wasn't already done - but it's a fun topic so I'm doing it immediately What I've gathered about at least the 991 series Porsches they use a combination of a boost sensor and throttle area vs angle calibration, though I could be wrong - am definitely riffing off bits and pieces I've been told. I *think* it's the 991.1 that has just a pre-throttle pressure sensor and the 991.2 has one on both sides (the post throttle one being more for diagnostic purposes ?!) - I'm guessing from that there are possibly a bit more like how the Motec R35 GT-R package does things, where it uses pre-throttle pressure and throttle opening vs flow data and engine efficiency data to estimate manifold pressure on the other side of the throttle. So if you think of an Emtron which (if I understand correctly anyway) is solving for mass flow using pre-throttle pressure, post throttle pressure and throttle angle - these guys are effectively solving for MAP by using pre-throttle pressure, throttle angle data and engine flow data. I could be wrong, but if it's anything like that then in my head it's going to get around the situation where there isn't a large pressure differential across the butterfly, but also creates a reasonable amount of calibration work to make it work right. In that sense it makes MAF a no brainer for the K.I.S.S philosophy, but then you were earlier criticising how limiting standalones are vs OEM ECUs. The joy of modern OEMs (and high end stand alones like Motec M1s) is there is a fcuk tonne of calibration to be done to make it work right but if you do then you get something that is super consistent and responsive to transient conditions. I believe much of the reason that the Motec M1 (and I assume modern Porsche ECUs) do this kind of thing is there is a latency between what the MAF is reading and what the engine is actually receiving. I hope this kinda makes as much sense as it can and it doesn't end up looking like wordsalad when I read it tomorrow after a good night sleep.

Good shouts, because the quoting on this is annoying I'll try and address them bit by bit: Misfire detection: Of course! Would love that and have discussed this with people who do aftermarket ECU development and the likes. That doesn't really negate anything I've said, but definitely a thing that would be cool. Standalones improving to suit the CAN/GDI ages: Tricky one, there is soooo much constant chassis and other bit bespoke development that it's hard to see how viable making something that can do everything would be without making it programmable, like Motec M1 Development. FFS, I pressed shift-enter hoping to make spaces between the points and it posted my comment part way through. Fwiw I'm still working on it...

I've been seeing all the email notifications for this thread and kinda interesting to see a bunch of tuning chatter. All seems pretty legit really, just thought I'd meander in and add 2c where it feels like they're not being so redundant. The more data you can get the better really, but it doesn't mean it's needed - really a lot of it is personal preference and there are a lot of different people who have different reasoning for different things which can all seem "reasonable". I find it odd that a tuner would say they wouldn't touch something without a wideband and oil/fuel pressure though, sure both are sensible but realistically he should be able to tune without those... they are just good additional precautions. They definitely make the tuning and diagnostic process easier, I guess if he can be that bossy then good on him I'd still not use the car's wideband for tuning, I prefer to use an external one (like on it's own power source etc) that I know I can trust and then verify the car's wideband against it to make sure everything is working right. There are plenty of cars that have had widebands installed and potentially even have closed loop running etc off them where they've never been checked and are likely reading off and has potentially the tune isn't doing what people have intended from them. A lot of variables at play with everything and as always, the more data the better. It'd be great if everyone had EMAP, EGT, MAF, turbine speed, pre and post intercooler pressure, knock, coolant, oil and fuel pressure, hell cylinder pressure would be nice too But theres are not NEEDED, but if we pick the right ones for what the car is doing and what fits the budget etc we can do a small subset that ideally ends up just being "nice to have" to help identify issues before they become serious, or help resolve issues after the fact. Hell, may be an unpopular opinion but if someone is trying to keep the amount they're spending down but want the car to have some safety then I tend to lean more towards fuel pressure than lambda for safety. A lot of tune drift and lean out issues seem to come down to fuel delivery, so while monitoring lambda and adjusting or reporting on error is definitely handy - if the tune is dialled in well realistically fuel pressure is often more than capable, potentially better at catching most issues have where a lean out could happen. I've rarely seen issues where uneven injector flow is the cause of a lean out (and almost any issues I do know of have been due to people using gas injectors, silly idea) and you could have a single injector lean out enough to hurt it's piston but not actually see a massive lean out at the wideband. Ie, 11.5:1 on 5 cylinders and 13:1 on #6 = an average of 11.75, a closed loop correction on that will make 5 cylinders a bit rich and the 6th one still lean and simply mask an issue and I'm not sure if most people would do an engine protection on .25 off target AFR. Another issue with relying primarily on closed loop is that exhaust leaks and misfires can set it off into weird places. A decent exhaust leak will set closed loop off dumping a heap of fuel into an engine that doesn't need it (though monitoring trims will help pick up on these things so it IS a handy diagnostic) and things can get pretty weird if you get a misfire on a cylinder, closed loop can start trying to throw heaps of fuel at the thing and make the whole engine run like shit and make it hard to immediately work out that it all started on a single cylinder losing spark and adding to the mess by fouling all the plugs. With fuel pressure being the "main guy" the overall fuel model tends to be more accurate if set up correctly, and it can also step in if you start getting a pressure drop - both bumping up injector open time to compensate for would otherwise be a brief lean out, or going into engine protection before a lean out ever happens... while lambda based safety tends to rely on the engine already leaning out (and probably way too much) before doing anything about it. I'm far from saying having O2 feedback is not worth it at all, just throwing other things into the discussion. The more data the better, but data definitely needs context to be used optimally. Now that I've mentioned misfires, another thing that surprisingly I've not noticed mention of so far is knock sensors, whether or not you use actual knock control. That's another thing that potentially will pick up on dangerous operating condition as quickly as a wideband will (not that you want to wait for it to reach that point), with the added advantage of being able to use windowing to identify which cylinder is responsible. Another neat thing about using windowed knock monitoring is a car I was involved with had fuel pressure, knock logging, lambda etc and it dropped a cylinder in a run. Lambda went lean on a bank, fuel pressure was fine, and the noise from the knock sensor during one cylinder's "turn" dropped way off compared to the rest. Replaced the coil on that cylinder, was running on all cylinders again and life was good. Without that range of sensors and the ability to make sense of what they were doing that whole diagnostic process could have been a much bigger headfk. < Misfire log Not trying to be a dick, I actually rate using a MAF if it's an option - they're pretty cool for the reasons you've implied... only reason I'm contradicting you is there is more "interesting stuff" (well I find it interesting) in the details that contradict you there. Porsche, Ford and BMW (and others) don't use MAF for load reference on a lot of their current high end cars. Some of them even still have a MAF sensor but it's more for diagnostics and other general control stuff, as earlier - more data is always good even if you're not relying on it. Speed density tuning has often been considered less accurate but these days with more understanding, better sensors and better processing hardware it's damn hard to beat and also ties into load based tuning very very well as part of the calibration process you effectively are building a reference table of how the cylinders are filled under given conditions without needing to hit them, which means you can basically forecast what you need to give the engine to make x amount of torque before the fact and then hit that torque level very quickly. This is particularly relevant to BMW and Porsche (the ones I know off hand at least) that don't actually use a traditional speed density setup where you have VE numbers in a MAP x RPM look up table, but they use a combination of boost pressure, throttle angle (and data on what the throttle's volumetric flow is at different angles), and MAP to calculate engine load/torque, either before or after the fact. This means that they're able to demand a target boost and throttle position to hit a torque target with less messing around than you could hope to with a conventional speed density setup, let alone with a MAF based system. The accuracy of the load calculation is very on point, way more responsive and accurate in transient load conditions and again - you can "plan ahead" in terms of controlling throttle and boost to hit precise torque targets very quickly. If you've ever wondered how current generation Porkers are so ridiculously consistent and controlled with power delivery, that's absolutely part of it. In terms of the grid of buttons, I don't have a lot of suggestions. I think most of the time it seems nice to have but if you're struggling to think of things to use them for then you probably don't need to set them up right now. The ones mentioned make sense enough (as much as pops & bangs etc make me cringe and feel for the hardware). I'd consider setting up a boost control mode that is effectively a torque limit per gear setup where you kinda have your cake and eat it too boost wise. When I've tuned >500whp stock gearbox GTSts I've given them reduced power in first and second, third gear I hold a peak torque level that is maybe adventurous but not suicide - but hold that torque to redline (so you still make decent power) and send them to the moon in 4th upwards. I personally reckon it's a really nice way boost targetting setup for RWD Skylines for various reasons, they don't really feel super held back but also are easier to drive fast and without breaking things. So I guess you could have a "valet mode", a "fast but under control" mode, and a "dumb cnut" mode where you send it to the moon in every gear and situation. Anyway, sorry for the wall of text - thought I'd throw some of that into the yarns... hope it's not TL;DR or too off topic Be interesting to see where you end up with it.

I reiterated them in the comment you just responded to so it would make it easier and make it clear I wasn't just being randomly grumpy haha. I am not trying to have a go, just trying to make it clear more info is needed from you to try and give you input which is as helpful as possible. Like if you were asking me what I'd put on your car if it was mine I'd be able to answer easily but the whole point here is trying to help you achieve what you're looking for with minimal compromise.

Honestly you aren't giving much to work with at all, my last post was effectively a "questions that need to be answered" one and you've responded to it with questions. If you want anyyyy kind of answer that isn't taking the piss the more of these questions you can answer the better: - What limited it to 520kw @ hubs in the first place? Is there timing on the table? Was there anything else to be sorted which could result in more at that point? What is your tuner's view on it? - WHAT IS THE LOWEST POWER TARGET AT THE HUBS YOU'D BE HAPPY WITH? And what octane fuel do you want to achieve that on? There is no point worrying about response if you're going to be constantly disappointed with the power level. - If you're hazy on the above, are you looking for a fun fast car or a big power figure? You have to choose to a degree here. If you're sticking to pump gas and the current setup is reasonably far short of what you want then an EFR is *not* for you - so you're going to be taking a decent response hit no matter where you go. The more info you give the easier it will be to try and help, but I'm not agreeing or suggesting to any turbo until you fill in some blanks.

Looks to be carrying power reasonably well, the boost control solenoid duty cycle can often paint a picture of EMAP. If the duty cycle is picking up a lot through the rpm range then EMAP is likely to be running away - if you're holding fairly steady WGDC....so if you hit target boost at 4500rpm and it stays at a fixed duty cycle area from there until 7500rpm to hold the same boost then EMAP probably isn't out of control. If it gains 10+% then it probably is. Reason is here is you're having to compensate for the raising exhaust pressure against the wastegate valve

Ahhh the joys. I'm not going to make any assumptions on what you've tried or thought of, so just going to dump some thoughts haha. First area to consider, comparing the actual dyno results it's worth trying to see the wood for the trees Autos are a headfk when doing dyno testing at the best of times. For the last few years I've been tuning a mates Toyota he dragraces - it had been running a 1.5litre 4cylinder turbo engine through a 5-speed manual and got it down to the mid 10s before the W58s became an item to be replaced every meet. To resolve the issue he chose violence, and dropped a 2JZGE (with added Pulsar G35 900) onto the side of it and attached a Powerglide to it to get it running. It took him the whole offseason to do all that work and ultimately got it to a point it was able to start and run with the old diff he had with the W58, and the fuel pump setup for the 4cylinder. The 10.58 @ 131mph he achieved was 320rwkw with the dyno we use for this car, fuel pressure all looked sweet... however with the 2JZ the same fuel pump setup was dropping pressure badly at only 286rwkw. All indications were the it was swallowing heaps of more air than the old 1.5 even though it was running VERY little boost and the power was much lower, but the airflow / fuel flow numbers otherwise appeared to be adding up correctly. Seemed to be happy and healthy so we figured just get it to the strip and do some shake downs. Long story short, despite the new engine/gearbox combo likely adding 100kg odd to the weight of the car and making less power on the dyno we ended up coaxing it down to a 9.78 @ 138mph (crossing the finish line on the limiter because out of gearing). Heavier car with less measured power. Of course there are other variables at play, but at the end of the day the fuel flow and the MPH vs weight suggest the thing was making a significant amount more power than it was with the 4cylinder. Autos do weird shit. Comparing two different dynos isn't going to help the comparison As per our experience, sometimes the dragstrip can give you more of an idea than the dyno will when autos are involved. Maybe worth driving it or getting it down the strip before making any hasty calls - may turn out to be combo that works better than how the dyno number makes you feel. Second major thing to consider which kinda branches from the first is that when choosing a turbo you have to work out how much airflow you need, or maybe more to the point - are actually going to be making decent use of and is going to suit your setup: The whole topic is one you should be discussing with your tuner, but this would be the most poignant one - what held you back from making more power? 98+WMI is arguably a lot less potent a fuel than E85 etc, depending on the blend and how your tuner has chosen to use it. If for some reason "all the timing" that the engine needs to make optimal use the air/fuel mix in there hasn't been dialled in then you potentially have a turbo capable of making more power than it is if the fuel (or the tuner's confidence in it) isn't there. It's worth knowing if part of the reason the power isn't as high as expected is because the tuner hasn't been able to lean on it and there is power on the table with higher octane fuel, as if there is then a turbo upgrade may not get the significant gains you're hoping for as the turbo may not have been the key limitation at this point. I'm not saying this is the case, I don't have the data to know it but plenty of people have been in this kind of situation and done a turbo upgrade with underwhelming results because of this kind of reason. As @GTSBoyindicated, data is king. If you had turbo speed/emap/whatever data you'd be in a much better position to estimate yourself how responsible the turbo itself is for limiting power - ie, if the airflow is there or not. Bare in mind, the EMAP or turbo speed being high just means your turbo isn't going to be able to give you more air... if the tune is held back at all (refer point 1) then it could still mean better octane fuel would be money better spent than a turbo upgrade. Worth speaking to tuner if you want to get an idea of where things are at there if you have any doubt of that, you may gain more power per psi with a bigger turbo but if you want a significant amount more power then more boost is probably going to be necessary to get the extra airflow which is pointless if your tuner isn't happy with the fuel you're using at that point. Now to actually TL;DR answer to your questions: 1) See how it drives and how it goes on the track before getting too concerned about power figures - esp. when you get an auto involved. 650whp through an auto could be a much faster car than you're expecting it to be, maybe. Turbo may or may not be tapped out but because of how hard the tuner is pushing it and how the auto is delivering that to the wheels its hard to know how much to blame the turbo for the 650whp figure. This will put you in a better position to decide whether upgrade to the G40 is going to be worthwhile. 2) Housing will depend on how concerned about lag you're going to be. I'd be tempted to swing the .95 if you are concerned at all but if you're trying to make a big step up in power it's probably worth not being shy.

Late to the party, I feel like I've been involved in a few conversations about this setup here and elsewhere and I feel like it's a thing which is going around in circles so I'm going to keep it to bullet points addressing whoever they may be relevant to. Correct me if any of my assumptions are wrong here. There are various mentions of E85 tuning on here, I'm pretty sure this is running BP98? 30c intake temp is NOT high If you are running 24psi on a responsive setup and still have under 30psi EMAP when getting near the end of the compressor flow of the turbo that is really good. 1:1 EMAP vs IMAP and below that are great to strive for, but going over that is not a problem if it's within sensible levels. The ratio based off the logging in this case is not cause for concern at all, however... While the max compressor speed for an EFR9180 is 116,000krpm and you're "only" at 103,000rpm - 103,000rpm is still off the map in this case, note the red dot. When you go under 60% compressor efficiency everything starts getting a lot harder, the compressor air temp goes up heaps and your intercooler has to work harder to get IATs in check - the turbo has to work harder to get any more flow and EMAP starts creeping up. I'd call this setup fairly maximized without being stupid about it. So yeah, at least for pump gas this is probably the right place to call it - both tuners seem to be it pretty close territory with each other and the data lines up that you're near the end. 1000hp @ engine (if you're aiming for at the wheels then it ain't happening at all) is an ambitious target on an EFR9180 on a big engine, that turbo is actually probably better suited to smaller ones that need more boost to achieve those numbers. There are mentions of the cam timing, again - you are turbo limited at this point. Doing things to make the setup work better psi for psi is going to make it WORSE, not better in this case as the 9180 is happier at higher boost. If you dial the cams in a way that they are going to need less boost to make the same power, you're going to shift to a less happy part of the 9180's comp map and it's going to be even less happy than it is at the moment. Ironically if you go the other way, you're going to potentially start struggling with octane limitations. Things like cam spec, cam timing etc increase your engines ability to move a volume of air but it doesn't matter much if the turbo can't efficiently push dense charge at the volume you want at the boost you're trying to push. The ways of making more power at this point in my opinion are: Use a fuel that allows you to get more power out of the amount of airflow you are moving (ethanol, methanol, nitromethane hahaha) Add more air to the combustion process somehow... ie, nitrous oxide. Do changes which increase mechanical efficiency, like dry sump etc. That's only going to offer incremental gains though, none of these (well short of nitrous or nitromethane - but don't do that haha) are going to get you to a legit 1000hp. To be clear with the "out of turbo" thing, you are out of COMPRESSOR here - not turbine. Don't get sucked into the idea of going a larger turbine housing with this, it may let a tiny bit more power happen but you're just freeing up flow for a compressor that is pretty much out of breath and for a setup which is only barely past 1:1 EMAP/IMAP. The most obvious thing to help this combination would be a compressor which has more to offer, like going an EFR9280 (or bigger). You're still going to reach a point where you should run better fuel at some point, but a 9280 seems like the nicest compromise to get gains without losing lots of response or anything like that. Those are my thoughts, anyway. PS: @GTSBoy, matchbot is educated guesses at the best of times - pretty subjective so I'm hardly going to rip on it My only comment, and I'm not assuming at all that you don't know this but just for yours or anyone elses interest... adding compressor efficiency to the table base off where the associated "dot" on the compressor map makes a difference to all the calculations eventually ending up affecting turbine efficiency/emap, so is worth doing if you cbf. Often isnt a biggy buuuuut in cases like this where you're starting to go off the comp map it can show you how much "damage" it's going to do.

Fwiw any time I've heard of or been involved with using GPS for this kind of thing it's turned out that GPS latency is too bad even it's fast. Remember the GPS speed is a "in hindsight" measurement, so it basically checks how long it took to cover ground and works out the average speed required to take that long... Which means you'll be going faster than what you've got from the GPS setup. The results I've seen are as you'd expect, basically it cuts the wrong amount and too late - could argue that the tuning could be tweaked for it but you are actually trying to make decisions based off things which have already happened which is going to be flawed. With 4wds I think accelerometers or predefined torque profiles for the situation are the less problematic way to go about things like this depending on how precise you want to be.

Any idea if some of the SX-R upgrades are going to flow over the to EFR range? The compressor map for the S200SX-R 7670 (/ S258SX-R?) looks like a cracker and could only imagine similar aero would make a worthy and needed update for the EFR7670:

Not an RB, but the nost recent result I've seen, and one of the more impressive is this 3litre VVTi 2JZGTE making 1130hp @ hubs with 30psi by 4000rpm on an EFR9280: https://fb.watch/kiHcr8Bydb/

Not at all. And this is a key point, aside from my wind up comments I made last night a few rums in after seeing morboost's smarta55 comment to someone who was simply stating their own preference as an opening to be a smarta55 myself - I have always been a huge fan of matching parts of a build to suit the purpose. I ultimately completely agree with you in terms of the stock R34 twins, or a mild twin setup for a mild fun street friendly setup. I'd never go out of my way to convince someone to go single turbo if they're aiming for under 350kw on a mild RB26 - the reasons I suggest a single turbo is better than a twin setup are not applicable at this point and if I myself were building a GT-R for that kind of purpose it's also how I'd probably do it. This again comes down to me mostly being pretty agnostic about brands or methods of doing things, and just trying to identify the most appropriate combo to achieve a purpose... which can include satisfying things the person who is going to drive it prefers even if they aren't specifically about peak performance. So yeah, realistically having an EFR8374 and saying that a single turbo or a EFR8374 isn't a great choice when you're using it for <350kw is bizarre when framed as a "people said and EFR/single turbo is best but its not" when it's a painfully poor match for what you're using it for is a kinda odd take. I'd never argue that you made the right choice going for that for this setup, or any single (though there are singles which would be wayyy better suited). The whole single turbo debate for me has LONG been about where people are running twins and trying to bend physics to make them work in highly restrictive setups and ending up needing to over turbo, massively engineer and strain the hell out of things to achieve numbers because of packaging limitations with the low mount twins - you end up with turbos not work in a balanced manner and both having to work WAY harder due to operating in temperatures and pressure ratios that a single turbo wouldn't have to when trying to move enough air to make >400kw @ wheels as you can package it well enough to draw in air and dump out exhaust without dealing with major choke points or trapping heaps of heat. That is not relevant in the case of what you're doing.... as such I am very pro twins in the right situations, and very pro single turbos in the right situations, and the same goes for picking brands of turbo, split/single pulse exhaust housings and the rest. One size fits all is not a thing that works with tuning cars, and having a personal preference is a very legit reason for choosing one thing over another - which again was the only point I made a dig, because two things that get my on my soap box are people choosing the wrong things for a job and then saying they're shit because they don't do that job properly, and people telling people their opinion is wrong

This is completely irrelevant to anything. Dose pipe was saying what he prefers for his own car, your opinion is irrelevant there. Also you mentioned a bunch of things where there is a compromise for a car used on the road, single turbo makes driveability and maintenance better than twins so is basically win win for a street car.

You're saying he wouldn't, and instead would inexplicably opt for sticking with rubbish transient response and generally ineffecient low mount twins despite knowing better?

Solid, a bit hard to tell much from the info though - no rpm scale or anything. What fuel is this, and the rest of the setup? Hub dyno? What does it spool/drive like?

Nice work, congrats on the result and cheers for sharing - have been pretty sure that it should be able to make more even with that housing. Looks like a nice fun delivery too, glad its making more the kind of power it should be now

Yeah 100%, glad it seems like its working out well so far - this kind of thing is 100% a thing I've been viewing the G-series range as having some advantage over. Also have a soft spot for the "single scroll RB sound", and a gripe I've had about the EFRs are how messy things end up having to be to run twin scroll and also the busy comp housings. Look forward to seeing how further meets go and if some more comparative data (like are you likely to get a dyno overlay?) would still be interesting. Cheers for updates and impressions, all very interesting and helps clear up some speculation

Awesome, was hoping it'd end up something like that, sounds probably like similar spool/response (and probably not miles off the flow) of an EFR9180... which is perfectly acceptable on a 2.8litre track car, especially with variable cam timing. Glad it's working out so far. Yeah, the single scroll setups definitely have a particular sound to them and the G-series aren't too bad with transient response compared to the GTx series Garretts and especially Precision turbos so while you're giving away response that you could have with an EFR it's not really likely to be a problem. As you said above, for a street car it'd be where it really makes a difference - like the EFR8474 doesn't sacrifice any flow over a G35 900, or noticable response over a EFR8374 buuuuuuut doesn't have the packaging and flexibility (or sound) advantages your new turbo have. Look forward to seeing an overlay to see how things go when you wind it up!

For you that's probably the case, the beauty with building cars is we can build what suits ourselves and we're not all forced to the same path. I've been around heaps of multipurpose builds that a single boost target configuration would not suit at all. If you have a car that is a weekend car that at events will run drag tyres and has potential to make a cr@pload of power but is still road friendly enough to be used for road trips etc then you really don't want to run the "run the quickest time you can on a drag radial" tune when you're going for a road trip on New Zealand running normal street tyres, I understand the "right foot" argument but straight up - sometimes when you're going to be driving for 9 hours on varying road surfaces, windy corners etc etc you don't want to have think about how much throttle you can give it every time you catch a campervan or truck with a small passing opportunity on a windy road. Maybe I'm a pussy, but I like having the option of just being able to roll on the throttle and blow past things without worrying about the car getting all frisky if I'm too heavy footed - buuuuuut also reserving the option to go "Screw it, I want to overtake a line of cars baking the bags"

ftfy

So I have the intake, the charge pipes, the XHP tune and MHD Stage 1 tune done on the car and jesus - it's actually QUITE a significant improvement. Will do the dump pipe and tinker a bit with the brain after that, but for such mild mods it is not at all a slow car and very very fun to drive. I am loving the hell out of having something that drives so nice and my not-car-people like the car as just a "nice car", gets around 7l/100k on the open road or 9l/100k around town (basically better than the Hondas I started out modifying but WAY faster) but I can do petrol head things and enjoy it more than anything else I've had. I think with the dump pipe and keeping the turbo at a point where it's not too strained should keep me happy for quite a while.